The factors associated with poor short-term recovery from knee surgery appear to be different than those found to mar long-term outcome from the same surgery, according to new research released at the 2007 Annual Meeting of the American Orthopaedic Society for Sports Medicine at the Telus Convention Center.
"We found that women showed poorer short-term recovery than men in the first year following arthroscopic meniscal tear removal surgery, and people with osteoarthritis also did not do as well as others," says principal investigator Peter Fabricant, BS, a medical student at Yale University School of Medicine in New Haven, Conn. "The factors associated with a poorer long-term outcome, such as larger tear size, greater amount of tissue removed, advanced patient age, and higher Body Mass Index, are not the same as those we can associate with short-term surgical recovery."
The meniscus is the shock-absorbing tissue that cushions the knee joint preventing the bones from rubbing. Tears in this tissue can cause pain and loss of function. In arthroscopic partial meniscectomy, the surgeon inserts small surgical instruments and a camera through tiny incisions in the knee to remove torn tissue. An estimated 636,000 arthroscopic knee procedures are performed annually, according to the American Academy of Orthopaedic Surgeons.
Fabricant and colleagues at Yale University studied 126 patients who underwent arthroscopic partial meniscectomy to assess the impact of obesity, age, gender, amount of tissue removed, and degenerative joint changes on short-term recovery. They found that being female and the extent of osteoarthritis were associated with a less-than-optimal first-year recovery.
Other studies have shown that advanced age, obesity, and the amount of meniscal tissue removed all negatively affect long-term outcome from arthroscopic meniscal repair. "In our study these variables did not affect short-term recovery. Conversely, gender and osteoarthritis appear to play a role in short-term recovery, as they have been shown to do in the long-term," Fabricant comments.
The current medical literature only offers research findings on long-term outcomes following arthroscopic meniscal repair. "We couldn't find anything in the literature to predict recovery during the first year," explains Fabricant. "Physicians need to be able to discuss with patients how long it might be before they can return to optimal function levels in work and activities of daily living."
Fabricant and colleagues suggest that severe osteoarthritis in the knee may be a contraindication to surgery. "Arthritis may be a marker for a degenerated knee, which may not be able to recover as well as a healthy, non-arthritic knee," Fabricant says.
Osteoarthritis may also be a marker for worse overall knee function in general. Patients with severe osteoarthritis already have loss of cartilage and soft tissue. Further tissue removal appears to have minimal impact on patient knee pain and function during the year following surgery.
The investigators say that it is unclear exactly how female gender complicates surgical recovery. Fabricant notes that there are gender differences both in surgical outcome and possibly in the biomechanics resulting in how the knee was initially injured. Even before surgery, women typically reported more knee pain and decreased knee function compared to men.